fix: allow hosting hash apps from other html files (#14825)

Fixes #14824.

Simplify by just checking if we're still on the current pathname

---------

Co-authored-by: Simon H <[email protected]>

Author: lishaduck

.changeset/upset-parents-sniff.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: allow hosting hash-based apps from non-index.html files

packages/kit/src/runtime/client/utils.js

@@ -317,16 +317,7 @@ export function is_external_url(url, base, hash_routing) {
 	}
 
 	if (hash_routing) {
-		if (url.pathname === base + '/' || url.pathname === base + '/index.html') {
-			return false;
-		}
-
-		// be lenient if serving from filesystem
-		if (url.protocol === 'file:' && url.pathname.replace(/\/[^/]+\.html?$/, '') === base) {
-			return false;
-		}
-
-		return true;
+		return url.pathname !== location.pathname;
 	}
 
 	return false;